Bottom of the body. The steering and drivetrain are both split into two parts, the engine itself and the time-honoured "hand of God" steering by a knob on roof, and the V6 engine that is grouped with the body, taking a page from the 8858 manual. See the chassis attachment points.
The back. The tail lights was modded back when I built 4404 per instructions before coming up with ideas for BB. The blue knob is the HOG steering knob. (Snow removal vehicles have trans blue beacon in Canada.)
Body and chassis. The rear is a traverse pendular axle straight from 8435. It really helped. The chassis is designed to follow the profile of stock chassis as closely as possible, so it will fit in nicely.
Check out the clutch gear here. It is part of the drivetrain. The axle going through it is for steering. When the body is secured, that part of both geartrains will engage nicely with their chassis sections. The entire front end has ideas from 8858, and 8465. Earlier prototypes was based on 8435.
i had this model it was the 1 lego model i kept fully built for the longest time i kept it built for like a year and a half everyday i used to add little bits to it mine had pneumatic suspension then one day i got so fed up with it i smashed it and put it in a bag a week later i looked at it and thought im gonna put it back together and give it another go it is my all time favourite lego model i knew the model inside out i could build it without instructions infact i miss it that much im gonna get another an do everything i can to it thanks for bringing back childhood memories :)
Great engineering job, considering one of the main complaints with this set IS it's lack of steering. Although I don't own the set, It'd be great if you could put up instructions for the mods required.